Subcutaneous medical devices may be implanted within patients (e.g., under the skin of patients) for various purposes including treatment of various conditions, disorders, diseases, and/or other maladies. For example, one type of subcutaneous medical device may be a subcutaneous neuromodulation system that includes (e.g., is implemented by) a coin-sized and coin-shaped electroacupuncture (“EA”) device implanted beneath a skin surface of a patient at an acupoint. The EA device may include an electrode configuration (e.g., a central electrode of a first polarity centrally located on a surface of a housing of the EA device, and an annular electrode of a second polarity and that is spaced apart from the central electrode) that is configured to deliver stimulation pulses to tissue of the patient at the acupoint in accordance with a stimulation regimen in order to treat a condition, disorder, disease, and/or other malady associated with the acupoint.
In some examples, it may be desirable to communicate with a subcutaneous medical device implanted within a patient from a location external to the patient. For example, it may be desirable for a person (e.g., a physician or other medical practitioner associated with the patient, the patient, etc.) to be able to easily, accurately, conveniently, and/or non-invasively control the subcutaneous medical device to, for instance, turn the device ON or OFF, start or stop particular operations of the device (e.g., start or stop stimulation sessions), modify characteristics of device operation (e.g., intensity, duration, and/or other characteristics of stimulation sessions being applied), and so forth.
Unfortunately, conventional forms of wireless communication, where information is modulated onto electromagnetic carrier waves and transmitted and received using antennas, may present challenges in the context of wireless communication with subcutaneous medical devices. For example, subcutaneous medical devices may be extremely small (e.g., coin-sized) such that components (e.g., antenna coils, etc.) required for conventional wireless interfaces may not fit within a housing of the subcutaneous medical devices. Additionally, subcutaneous medical devices may use power extremely judiciously (e.g., so that a single-use battery may power the subcutaneous medical device for several years without being replaced), and it may be difficult or impossible to implement a conventional wireless communication interface under such stringent power usage restrictions.
Certain subcutaneous medical devices have avoided the problems associated with conventional wireless communication interfaces by providing some amount of control based on externally-generated static magnetic fields, which may be detected by the subcutaneous medical devices using very small and low-power components. However, operations controllable using only a presence or an absence of a static magnetic field have been limited to binary, ON/OFF-type operations. It would be desirable to be able to send more complex and varied commands to the subcutaneous medical device.